A thermoplastic elastomer composition obtained by melt-kneading a composition comprising an ethylene random copolymer rubber and a propylene polymer is used in the various fields of automobile parts, various industrial parts, and various architectural materials by taking advantage of its flexibility. For example, Patent Document 1 describes a thermoplastic elastomer composition obtained by dynamically heat-treating an ethylene-α-olefin copolymer rubber and a propylene polymer in the presence of a crosslinking agent.